A metal-sealed soluble packer

Abstract

A metal-sealed soluble packer relates to the technical field of oilfield downhole tools, comprising an upper joint, an upper center pipe, a soluble upper cone, a soluble metal sealing ring, a soluble lower cone, a lower center pipe, a locking sleeve, a sealing piston and a lower joint, wherein the soluble upper cone, the soluble metal sealing ring and the soluble lower cone are located on the upper center pipe, the soluble upper cone and the soluble lower cone are wedged into the soluble metal sealing ring, the locking sleeve is threadedly connected to the soluble lower cone, the upper end of the sealing piston is connected to the locking sleeve, the lower end of the sealing piston is connected to the lower center pipe through a clamping block, the auxiliary piston limits the sliding of the clamping block, and the auxiliary piston is connected to the sealing piston through a sealing shear nail. The utility model solves the problem that the existing packer is easy to be blocked by sand and buried in sand when used for repeated fracturing of old wells, and the packer is difficult to unseal. The soluble upper cone, the soluble metal sealing ring and the soluble lower cone of the present application can all be completely soluble. After dissolution, the maximum outer diameter of the packer is the same as the outer diameter of the oil pipe coupling, and the pipe string can be smoothly lifted out of the wellbore.

Description

Technical Field

[0001] The utility model belongs to the technical field of downhole tools in oil fields, and particularly relates to a metal-sealed soluble packer. Background Art

[0002] Tight oil and gas reservoirs have poor reservoir properties, and horizontal well casing completion is often used for well completion. Multi-stage and multi-cluster volume fracturing is used for fracturing development. The initial production is high, but as the amount of remaining oil around the fractures decreases and the formation energy decreases, the production drops significantly. Repeated fracturing is required to transform the reservoir and increase production capacity.

[0003] At present, there are mainly three methods for multi-stage fracturing in casing of horizontal wells at home and abroad. One is the soluble bridge plug perforation joint process, which is suitable for new wells; the other is the packer plus ball-drop sliding sleeve fracturing process, that is, multi-stage packers are put into the casing, and every two stages of packers are stuck in a perforation section, and a ball-drop sliding sleeve is put in the middle of the packer. However, the strata near the wellbore of most old wells have undergone previous fracturing construction, and the wellbore has serious sand production. During repeated transformation, it is easy to be blocked and buried by sand, and it is difficult to unseal the packer; there is also a double-seal single-card dragging fracturing process, which also has the problem of easy sand sticking and difficulty in unsealing.

[0004] In view of the limitations of the above-mentioned technology, it is urgent to develop a packer for old wells suitable for repeated fracturing. Utility Model Content

[0005] In order to solve the problems in the background technology, the utility model provides a metal-sealed soluble packer. The utility model is a non-metal-sealed soluble packer that can be smoothly lowered to the designed position in a multi-stage well, can withstand high pressure during fracturing, can be automatically unsealed without other means, and can be smoothly pulled out of the wellbore.

[0006] The technical solution provided by the utility model is: a metal-sealed soluble packer, comprising an upper joint, an upper center pipe, a lower center pipe and a lower joint, wherein the upper center pipe is connected to the lower center pipe, the upper end of the upper center pipe is connected to the upper joint, the lower end of the lower center pipe is connected to the lower joint, and a soluble upper cone, a soluble metal sealing ring, a soluble lower cone and a locking sleeve are sequentially arranged on the outer side of the upper center pipe from top to bottom, the soluble upper cone is fixedly connected to the center pipe, the lower part of the soluble upper cone has a cone surface, and the soluble lower cone is slidably sealed with the center pipe. The lower end of the soluble lower cone is connected to the locking sleeve, the upper part of the soluble lower cone has a conical surface, the conical surface of the lower part of the soluble upper cone and the conical surface of the upper part of the soluble lower cone are respectively inserted into the soluble metal sealing ring, so that the soluble metal sealing ring can withstand the bidirectional pressure difference; the locking sleeve and the upper center tube are slidably sealed, the inner wall of the locking sleeve is provided with a locking tooth, and the outer side of the upper center tube is provided with a locking spring for limiting the one-way movement of the locking tooth, the locking spring allows the locking sleeve to slide upward and prevents the locking sleeve from sliding downward, and a pressure transmission is processed on the upper center tube below the locking sleeve Hole A, the pressure transmission hole A transmits the pressure in the center tube to the lower end of the locking sleeve, pushing the locking sleeve upward; a sealing piston is arranged on the outer side of the lower center tube, the upper end of the sealing piston is connected to the locking sleeve, the sealing piston and the lower center tube are slidingly sealed, a cylinder is arranged on the outer side of the center tube below the sealing piston, an annular space is provided between the cylinder and the lower center tube, a secondary piston is slidingly sealed in the annular space, a pin hole is provided on the lower side wall of the sealing piston, a card block is slidingly inserted in the pin hole, a trapezoidal annular groove is provided on the outer wall of the lower center tube, one end of the card block is against The other end of the clamping block is against the auxiliary piston in the trapezoidal annular groove on the outer wall of the lower center tube. The auxiliary piston is connected to the setting piston by the setting shear pins. Before the setting shear pins are cut off, the auxiliary piston does not slide, the clamping block cannot be withdrawn from the trapezoidal annular groove, and the setting piston cannot slide relative to the lower center tube. A pressure transmission hole B is processed on the lower center tube between the setting piston and the auxiliary piston. The pressure transmission hole B transmits the pressure in the center tube to the lower end of the setting piston. A spare cap is arranged between the cylinder barrel and the lower joint. The spare cap is fixedly connected to the lower joint and slides with the cylinder barrel.

[0007] A further technical solution is: a limit nut is connected to the lower center tube, and the lower end surface of the limit nut abuts against the auxiliary piston, thereby limiting the upward movement of the auxiliary piston.

[0008] A further technical solution is that all materials of the soluble metal sealing ring, the soluble upper cone and the soluble lower cone are soluble.

[0009] A further technical solution is that a wear-resistant and anti-dissolution layer is sprayed on the outside of the soluble metal sealing ring.

[0010] Compared with the prior art, the beneficial effects of the present invention are:

[0011] 1. The soluble metal sealing ring adopts the wedge-in method of upper and lower cones to expand and seal, which can withstand bidirectional pressure difference.

[0012] 2. The soluble metal sealing ring, soluble upper cone and soluble lower cone can all be dissolved. After dissolution, the maximum outer diameter of the packer is the same as the outer diameter of the tubing coupling, which is convenient for lifting the tubing string and not easy to get stuck in the well.

[0013] 3. A wear-resistant and anti-dissolution layer is sprayed on the outside of the soluble metal sealing ring. Under the protection of the wear-resistant and anti-dissolution layer, the soluble metal sealing ring does not contact the well fluid before setting. After setting, the soluble metal sealing ring expands outward, expanding the wear-resistant and anti-dissolution layer to contact the well fluid, and it can be dissolved after a certain period of time.

[0014] 4. The sealing mechanism is designed with an anti-obstruction mechanism to ensure correct operation when encountering obstructions.

[0015] 5. The double-stage sealing mechanism is designed to increase the sealing force, ensure that the soluble metal sealing ring is sealed more tightly, improve the sealing effect, and be able to withstand higher pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional view of the utility model.

[0017] Figure 2 yes Figure 1 A local enlargement of point A in the middle.

[0018] In the figure: 1. upper joint; 2. soluble upper cone; 3. upper center tube; 4. soluble metal sealing ring; 5. soluble lower cone; 6. locking sleeve; 7. locking spring; 8. setting piston; 9. lower center tube; 10. clamping block; 11. setting shear pin; 12. auxiliary piston; 13. limiting nut; 14. cylinder barrel; 15. spare cap; 16. lower joint. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] like Figure 1 As shown, the utility model includes an upper joint 1, an upper center pipe 3, a lower center pipe 9 and a lower joint 16. The upper center pipe 3 is connected to the lower center pipe 9, the upper end of the upper center pipe 3 is connected to the upper joint 1, and the lower end of the lower center pipe 9 is connected to the lower joint 16.

[0021] A soluble upper cone 2, a soluble metal sealing ring 4, a soluble lower cone 5 and a locking sleeve 6 are sequentially arranged on the outer side of the upper central tube 3 from top to bottom. The soluble upper cone 2 is fixedly connected to the central tube, the lower part of the soluble upper cone 2 has a conical surface, the soluble lower cone 5 is slidingly sealed with the central tube, the lower end of the soluble lower cone 5 is connected to the locking sleeve 6, the upper part of the soluble lower cone 5 has a conical surface, the conical surface of the lower part of the soluble upper cone 2 and the conical surface of the upper part of the soluble lower cone 5 are respectively inserted into the soluble metal sealing ring 4, so that the soluble metal sealing ring 4 can withstand a bidirectional pressure difference.

[0022] The locking sleeve 6 is slidably sealed with the upper center tube 3. The inner wall of the locking sleeve 6 is provided with a locking tooth. The outer side of the upper center tube 3 is provided with a locking spring 7 for limiting the one-way movement of the locking tooth. The locking spring 7 allows the locking sleeve 6 to slide upward and prevents the locking sleeve 6 from sliding downward. A pressure transmission hole A is processed on the upper center tube 3 below the locking sleeve 6. The pressure transmission hole A transmits the pressure in the upper center tube 3 to the lower end of the locking sleeve 6, pushing the locking sleeve 6 upward.

[0023] A sealing piston 8 is arranged on the outer side of the lower center tube 9, the upper end of the sealing piston 8 is connected to the locking sleeve 6, the sealing piston 8 and the lower center tube 9 are slidingly sealed, a cylinder 14 is arranged outside the center tube below the sealing piston 8, an annular space is provided between the cylinder 14 and the lower center tube 9, a secondary piston 12 is slidingly sealed in the annular space, a pin hole is provided on the lower side wall of the sealing piston 8, a card block 10 is slidingly inserted in the pin hole, the outer wall of the lower center tube 9 is provided with a trapezoidal annular groove, one end of the card block 10 is against the trapezoidal annular groove on the outer wall of the lower center tube 9, and the other end of the card block 10 is against the secondary piston 12 The auxiliary piston 12 is connected to the setting piston 8 by the setting shear pin 11. Before the setting shear pin 11 is cut off, the auxiliary piston 12 does not slide, the blocking block 10 cannot withdraw from the trapezoidal ring groove, and the setting piston 8 cannot slide relative to the lower center tube 9. A pressure transmission hole B is processed on the lower center tube 9 between the setting piston 8 and the auxiliary piston 12. The pressure transmission hole B transmits the pressure in the lower center tube 9 to the lower end of the setting piston 8, pushing the setting piston 8 upward. A spare cap 15 is arranged between the cylinder barrel 14 and the lower joint 16. The spare cap 15 is fixedly connected to the lower joint 16, and the spare cap 15 and the cylinder barrel 14 are slidably matched.

[0024] A limiting nut 13 is connected to the lower center tube 9, and the lower end surface of the limiting nut 13 abuts against the auxiliary piston 12, thereby limiting the upward movement of the auxiliary piston 12.

[0025] All materials of the soluble metal sealing ring 4, the soluble upper cone 2 and the soluble lower cone 5 are soluble. After dissolution, the maximum outer diameter of the packer is the same as the outer diameter of the oil pipe coupling, which is convenient for lifting the pipe string and is not easy to get stuck in the well.

[0026] The soluble metal sealing ring 4 is sprayed with a wear-resistant and anti-dissolution layer on the outside. Under the protection of the wear-resistant and anti-dissolution layer, the soluble metal sealing ring 4 does not contact the well fluid before setting. After setting, the soluble metal sealing ring 4 expands outward, expands the wear-resistant and anti-dissolution layer and contacts the well fluid, and becomes soluble after a certain period of time.

[0027] The working process of this utility model:

[0028] Sealing: The oil pipe is pressurized to allow liquid to flow into the two pressure transmission holes in the upper center pipe 3 and the lower center pipe 9. The hydraulic pressure generates a downward thrust on the auxiliary piston 12, shearing off the sealing shear pins 11, and the auxiliary piston 12 moves downward. The block 10 loses its external restriction and pops out from the trapezoidal ring groove on the outer side of the lower center pipe 9. The hydraulic pressure generates an upward thrust on the locking sleeve 6 and the sealing piston 8 respectively. The two thrusts are superimposed to push the sealing piston 8, the locking sleeve 6, and the soluble lower cone 5 upward. The soluble metal sealing ring 4 expands outward under the action of the conical surfaces of the soluble upper cone 2 and the soluble lower cone 5, fits the inner wall of the casing, and seals the oil casing annulus. At the same time, the locking spring 7 locks the locking sleeve 6 on the upper center pipe 3. When the oil pipe is depressurized, the locking sleeve 6 will not move downward, and the soluble metal sealing ring 4 forms a seal with the casing.

[0029] Withstand upper and lower pressure differences: Since the soluble metal sealing ring 4 can withstand bidirectional pressure differences under the support of the soluble upper cone 2 and the soluble lower cone 5, when the packer is subjected to the downward pressure difference, the hydraulic pressure acts on the lower part of the soluble metal sealing ring 4, pushing the soluble metal sealing ring 4 upward. As the pressure increases, the soluble metal sealing ring 4 wedges into the soluble upper cone 2 more and more tightly, and the sealing effect is better. Similarly, when subjected to upward pressure, the hydraulic pressure acts on the upper part of the soluble metal sealing ring 4, pushing the soluble metal sealing ring 4 downward. As the pressure increases, the soluble metal sealing ring 4 wedges into the soluble lower cone 5 more and more tightly, and the sealing effect is better.

[0030] Unsealing: The soluble metal sealing ring 4, the soluble upper cone 2 and the soluble lower cone 5 are all made of magnesium-aluminum alloy. The formula can be adjusted according to the mineralization of the well fluid and the formation temperature so that they can be completely dissolved within the specified time while meeting the working time. After dissolution, the maximum outer diameter of the packer is the same as the outer diameter of the oil pipe coupling, and the pipe string can be smoothly lifted out of the wellbore.

Claims

1. A metal-sealed soluble packer, characterized in that: The invention comprises an upper joint (1), an upper central tube (3), a lower central tube (9) and a lower joint (16), wherein the upper central tube (3) is connected to the lower central tube (9), the upper end of the upper central tube (3) is connected to the upper joint (1), and the lower end of the lower central tube (9) is connected to the lower joint (16), and a soluble upper cone (2), a soluble metal sealing ring (4), a soluble lower cone (5) and a locking sleeve (6) are sequentially arranged on the outer side of the upper central tube (3) from top to bottom, wherein the soluble upper cone (2) is fixedly connected to the central tube, the lower part of the soluble upper cone (2) has a conical surface, and the soluble lower cone (5) is provided with a locking sleeve (6). 5) is in sliding sealing cooperation with the center tube, the lower end of the soluble lower cone (5) is connected to the locking sleeve (6), the upper part of the soluble lower cone (5) has a conical surface, the conical surface of the lower part of the soluble upper cone (2) and the conical surface of the upper part of the soluble lower cone (5) are respectively wedged into the soluble metal sealing ring (4), the locking sleeve (6) is in sliding sealing cooperation with the upper center tube (3), the inner wall of the locking sleeve (6) has a locking tooth, and the outer side of the upper center tube (3) is provided with a locking spring (7) for limiting the one-way movement of the locking tooth, the locking spring (7) allows the locking sleeve (6) to slide upward and prevents the locking sleeve (6) from sliding downward, A pressure transmission hole A is machined on the upper center tube (3) below the lock sleeve (6); a sealing piston (8) is arranged on the outer side of the lower center tube (9); the upper end of the sealing piston (8) is connected to the lock sleeve (6); the sealing piston (8) and the lower center tube (9) are slidably sealed; a cylinder (14) is arranged outside the center tube below the sealing piston (8); an annular space is provided between the cylinder (14) and the lower center tube (9); a secondary piston (12) is slidably sealed in the annular space; a pin hole is provided on the lower side wall of the sealing piston (8); a card block (10) is slidably inserted in the pin hole; and the lower center tube (9) is provided with a pin hole. The outer wall of the core tube (9) is provided with a trapezoidal annular groove, one end of the clamping block (10) abuts against the trapezoidal annular groove of the outer wall of the lower center tube (9), the other end of the clamping block (10) abuts against the auxiliary piston (12), the auxiliary piston (12) and the setting piston (8) are connected through a setting shear pin (11), a pressure transmission hole B is processed on the lower center tube (9) between the setting piston (8) and the auxiliary piston (12), a spare cap (15) is provided between the cylinder barrel (14) and the lower joint (16), the spare cap (15) is fixedly connected to the lower joint (16), and the spare cap (15) and the cylinder barrel (14) are slidably matched.

2. A metal-sealed soluble packer according to claim 1, characterized in that: A limiting nut (13) is connected to the lower center tube (9), and the lower end surface of the limiting nut (13) abuts against the auxiliary piston (12), thereby limiting the upward movement of the auxiliary piston (12).

3. A metal-sealed soluble packer according to claim 1, characterized in that: All materials of the soluble metal sealing ring (4), the soluble upper cone (2) and the soluble lower cone (5) are soluble.

4. A metal-sealed soluble packer according to claim 1, characterized in that: The outer surface of the soluble metal sealing ring (4) is sprayed with a wear-resistant and anti-dissolution layer.

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